forgot the name

i read a manga a while ago and wanted to read it again but i can't think of the name. It was about this girl in high school and she is introduced to her step brother who is younger than her by a lot. the little brother is in love with the girl and gets in between her love affairs and in the end the girl realizes how much she loves the brother.I only remember bits a pieces of it but at some point in the manga, the boy works as a model for a short period and the older woman model is attracted to him. thanks so much XD